Have you read the user guide that came with the device?
Did you read the FAQ on here?
As for email, do you have a BB data plan?
Is your device properly provisioned by your carrier.
Have you resent service books?
Are you on BIS or BES?
Do you have "Leave Messages on Server" selected in you PC email client set up?
Were you receiving mail and it stopped all of a sudden? If so what did you do just prior to it stopping?